The Kerala State Disaster Management Authority (KSDMA) has recommended active intervention, including stringent screening on State borders, long-term physical distancing strategies, and effective quarantining, to forestall a sharp spike in COVID-19 cases in a post-lockdown scenario in Kerala.
This is how the situation can evolve if there is no intervention whatsoever when the lockdown is lifted (projections use April 14 as the starting point).
Hospitalisation can peak in the range of 4.8 lakh to 8.2 lakh cases between June end and July end, show statistical models constructed by an eight-member KSDMA team which has been trying to make sense of an unpredictable future.The possible scenarios were presented before Chief Minister Pinarayi Vijayan on Thursday.
In a scenario where break-the-chain measures, physical distancing or quarantining are wholly absent, symptomatic cases can peak at 48 lakh cases, hospitalisation at 4.8 lakh, and ICU admissions at 36,000 by July end if the infection is in the ‘low spread’ category.
If the infection spreads at a medium pace as per this model, by the beginning of July, symptomatic cases can peak at 65 lakh, hospitalisations at 6.5 lakh, and ICU cases at 49,000.
Given a worst-case scenario, the State can have a situation on hand by June-end with 82 lakh symptomatic cases, 8.2 lakh hospitalisations, and 62,000 ICU admissions.
Hospital bed capacity
The hospital bed capacity of 1,30,550 and ICU capacity of 8,693 in the State have been factored in to arrive at conclusions as they are critical to the management of any scenarios, say KSDMA sources. In a no-intervention, ‘low spread’ situation, hospitals will reach the tipping point by June end, and by the second week of June in a ‘medium spread’ projection. On the other hand, given a severe spread of the infection, hospitals will reach the tipping point by May end.
The KSDMA modelling suggests four ways to counter this: stringent screening on the borders, active break-the-chain measures such as use of masks, long-term physical distancing, contact tracing, and quarantining.
And what if the intervention combines all these measures? In such a scenario, symptomatic cases, hospitalisation, and ICU admissions will peak at 20,000, 2,000, and 200 respectively by April 2021 in a medium-spread scenario.
If the spread is severe, hospitalisation will peak at 75,000 and ICU cases at 7,500 by December end 2020. But even this will be manageable.
How modelling is done
The KSDMA team initially worked with the SIR (susceptible-infectious-recovered) model used for forecasting influenza. This was later refined and customised for Kerala factoring in susceptible population, exposed population, infected and contagious period, infected and non-contagious period, and recovery (SEIIR).
The team, led by member-secretary Sekhar L. Kuriakose, included Birenjith of the Government Engineering College, Barton Hill, who handled modelling aspects, and community medicine experts from the Government Medical College, Thiruvananthapuram, led by Associate Professors Anish T.S. and Ratheesh K.H.
